UNIX for Dummies Questions & Answers

What would be wrong with a simple

Code:

awk '{sum+=$0} END {printf "$%.2f\n", sum/100}' file
$600.00

(except for the caveat that corona688 pointed out)?

Hi.

Also utility numsum, part of:

Code:

num-utils - programs for dealing with numbers from the command line

in systems like:

Code:

OS, ker|rel, machine: Linux, 3.16.0-4-amd64, x86_64
Distribution        : Debian 8.0 (jessie)

For example, assuming numbers are in file data3,

Code:

numsum data3

produces:

Code:

60000

Best wishes ... cheers, drl

Floating point math. Good enough for some, not for others

FP varies so much and there are many different variables....

Avoid and you'll pass an audit easier!

Code:

A=`cat my_file.txt | awk '{sum+=$1} END { print sum}'`
B=$(echo "scale=2; $A / 100" | bc)

echo "$"$B

Using integers isn't the only point here. The size of the sum is what matters in this problem. Since awk uses double precision floating point arithmetic (even when processing integers), you can have a problem if the accumulated sum (in cents) is 15 or more digits (i.e., more than $999,999,999.99). So, if your final result is less than 1 billion dollars, RudiC's script should be fine. If your result could be bigger, you can use shell and bc or dc to get the results you want no matter how big the sum is:

Code:

#!/bin/ksh
(echo '2k0[$]P'; while read line
	do	echo " $line"
	done < my_file.txt
echo '100/pq') | dc

printf '$'
(echo 'a=0;scale=2'; while read line
	do	echo "a+=$line"
	done < my_file.txt
	echo 'a/100'
) | bc

On most UNIX and UNIX-like systems, bc is a front-end to dc. Therefore, I tend to use dc instead of bc to avoid creating the extra process. But, bc is in the standards and dc isn't. So, if your system doesn't have dc or you want your script to be portable to systems that might not have dc, use bc.

Both sections of the above script print:

Code:

$600.00

when your sample input is contained in my_file.txt.